Optical networks (i.e., fiber optic systems) utilize optical amplifiers such as Erbium Doped Fiber Amplifiers (EDFAs) in various locations including intermediate line amplifiers, receiving amplifiers (also referred to a pre amplifiers), transmitting amplifiers (also referred to a post amplifiers or booster amplifiers), add/drop amplifiers (on the add/drop side of an Optical Add/Drop Multiplexer (OADM), etc. On the line side in an optical section (between an OADM and a second OADM), there can be a transmitting amplifier, various intermediate line amplifiers, and a receiving amplifier. The conventional approach for communication and coordination between these devices is via an Optical Service Channel (OSC). For example, eye safety regulations or standards is one aspect that requires coordination between optical amplifiers. The eye safety levels are defined in relevant standards (e.g., ITU G.664, IEC60825-2, etc.) and require that optical amplifiers limit their output powers to an eye-safe level when transmitting into a broken/unterminated fiber. Power levels in standard Single Mode Fiber (SMF) in the 1550 nm window should be <10 mW or <136 mW to comply with Hazard 1 or 1M levels, respectively. In addition to complying with the eye safety requirements, it is operationally advantageous for the amplifiers to automatically resume operation once the fiber break is repaired. There are scenarios where no OSC is deployed on a fiber pair, such as in the case where an optical system utilizes multiple fiber pairs, i.e., only one OSC is needed for multiple fiber pairs. There is a need for shutoff coordination between optical amplifiers where there is no OSC.
On the add/drop of an OADM, there can be optical amplifiers prior to channel multiplexer/demultiplexers, such as in Colorless, Directionless, and Contentionless (CDC) architectures. There is typically no OSC on the local add/drop side for communication and coordination as the OSC is between nodes, not internal to a node. There is a need to determine/verify connectivity (topology). There is also a need to determine/verify connectivity on the line side as well, such as in the case of multiple fiber pairs.
Accordingly, it would be advantageous to have a system level framework for optical amplifier communication in the absence of an underlying service channel.